The term 'Reason for Sudden Death' can be summarized as a cause of death that occurs unexpectedly and without warning. The crossword solution for this term is 'TIE', which stands for Trauma, Infection, or Environmental factors. Trauma can refer to physical injuries caused by accidents or violence, infection can refer to illnesses caused by bacteria, viruses, or other pathogens, and environmental factors can refer to extreme weather conditions or exposure to hazardous materials. All of these can lead to sudden death if they are severe enough.